WASHINGTON (CNN) -- It was September 1967, and Lt. Cmdr. John McCain was back from Vietnam on home leave. He invited Chuck Larson over for dinner, and during a late night game of bridge, McCain pulled his buddy from the U.S. Naval Academy and flight school aside.

Navy aviator John McCain stands next to an aircraft in this undated photograph.

"You know Chuck, I might have to get out of the Navy," McCain told him. "And I said, 'Why is that John?' and he said, 'Well I want to be a serious naval officer. And when I go places now, people tend to not take me seriously. They hear all the stories, they look at the early days and if they can't take me seriously, I don't know how I can perform.' And I said, 'John, you're going back.' "

A few weeks later, McCain reported for duty on the USS Oriskany and, as he did on his previous assignment on the USS Forrestal, began flying bombing missions over North Vietnam.

October 26, 1967, was McCain's 23rd mission. His target was a power plant on the outskirts of Hanoi.

"I was still in the dive, I had just started to pull out and got hit by a surface-to-air missile, and it basically took the wing off the aircraft," McCain told CNN in one of a series of conversations for "McCain Revealed." "And so I was gyrating very violently, almost straight down, so I had to eject very quickly."

Retracing McCain's steps in Vietnam was a fascinating experience. On the shores of Ho Truc Bach -- White Bamboo Lake -- we spent time with Nguyen Dang Doanh, who said he was on the far side of the lake that morning when he saw a parachute splash down in the water.

McCain was "stretched out -- he was lifted by the life jacket," Doanh said. "Then we all pushed him here [to the edge of the lake] and the security forces surrounded him. .. At that point everyone in the village was here. Everyone came down to see the American pilot."

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Nguyen Thi Tranh was a nurse on duty at a neighborhood first aid station that day. Its purpose was to treat local residents hurt in the American bombardment, but Tranh remembers the day more than four decades ago when police came in carrying a white-haired American pilot.

Tranh, now 82 and living in a modest home not far from the lake, told us she bandaged McCain's arms and one leg. She said she "hated the American pilots" because of the deaths and destruction caused by their bombing runs, but she viewed it as her job and her duty to help treat him. See McCain timeline »

She would later learn that the man who was in her care for 15 or 20 minutes that day became a politician after he returned to the United States. "Would you like him to be president of the United States?" we asked Tranh.

Tran Trong Duyet was the director of the Hoa Lo prison, known as the notorious "Hanoi Hilton" to American POWs, from 1968 to 1973. He has kept track of McCain's political career, and said he admires the man once in his custody because of his work to push the United States, during the Clinton administration, to normalize relations with Vietnam.

As for his prison days, Duyet said in his conversations with McCain, "He would never admit the United States made a mistake in the war. ... Therefore I say John McCain is an extremely conservative man. He was loyal to his ideology."

The low point for McCain came in 1968, before his transfer to the Hanoi Hilton. In his own accounts of those days, McCain wrote that after four days of beatings -- including a re-breaking of his left arm -- he signed a confession admitting to war crimes.

"I wasn't as tough as I had hoped to be and I certainly wasn't as strong as some of my comrades," McCain said.

The Vietnamese knew his father was the admiral commanding U.S. forces in the Pacific, and they offered McCain early release. But he refused, on grounds the code of conduct instructed that prisoners be released in the order in which they had been captured.

"There was a correlation between my refusal to accept early release and my treatment," McCain told us. "Because after it was clear to the Vietnamese I would not do that, then the treatment got very much worse."

As for his father, who knew from U.S. intelligence that increased bombing could result in harsher treatment for his son, McCain said: "I think in many ways it was harder on him than it was on me."

Duyet grew animated and agitated when pressed about accounts by McCain and dozens of other American POWs who said they were beaten and tortured, including being hung from the ceilings of their cells with their hands bound behind their backs.

"This is not true, because our nation is civilized and humanitarian and you do not understand the Vietnamese nation," Duyet said. "We never beat anybody."

Ernie Brace is among the many who tell a different story of their time as a POW, including time at Hao Lo when McCain was there.

"I had my front teeth knocked out, I had my cheekbone broken, I had my nose broken," said Brace. He described other inmates who were, among other things, "beaten with a fan belt for three of four days." He said the captors would "put your elbows behind your back and tighten up the rope around your elbows until your shoulders dislocated."

Many of McCain's friends said he rarely brings up his POW days in their conversations, and won't discuss details of his treatment unless pressed.

"It's just a chapter in my life that I'd rather remember the good parts than the bad parts," McCain said. "I don't know what the point is of going through all that."

It was while in the cell next to McCain that Brace said he first got a sense of his neighbor's politics -- communicated through taps on the wall using an alphabet code developed by the prisoners. Watch Brace talk about their secret code »

According to Brace, when Richard Nixon was elected president in 1968, McCain was "elated."

"He said, 'Nixon will get us home. Nixon won't sit there. He'll listen to the generals and get, you know, no more running this war from the basement of the White House.' "

"Well, it didn't happen," Brace recalled recently. "We thought we'd be home for Christmas of '69 and there we were. And there we were for three more Christmases -- '70, '71, and '72."

And his take on his neighbor's politics back then?

"He was a conservative. He was an archconservative," said Brace. "And his theory on the war at that time was 'Do it. Do it right, and get it over with.' "